The present invention relates to a novel process for the production of a polyacetylene derivative and also to a polyacetylene derivative having a unique ability for discrimination of chirality obtained by the said producing process.
With regard to a substance having optical asymmetry, there have been known many substances such as that having asymmetric carbon and that having the so-called molecular asymmetry. Those substances have been widely used in industry as agents for optical resolution, materials for liquid crystals, chiral sensors, nonlinear optical materials and other functional materials.
Among those asymmetric molecules, high-molecular substances having molecular asymmetry have been receiving public attention in recent years and, for example, there have been known optically active polyacrylamide derivatives (Japanese Patent Publication No. 167708/1981) and poly(triphenylmethyl methacrylate) (Japanese Patent Publication No. 106907/1981) having a helical structure and a high optical rotatory power.
The present inventors previously found that polymers of (4-carboxyphenyl)acetylene showed an induced circular dichroism (ICD) of a disintegration type to optically active amines and amino alcohols in an organic solvent such as dimethyl sulfoxide (DMSO) (Japanese Patent Publication No. 176243/1997) and, due to such a unique property, utilization of them as chiral sensors and agents for optical resolution is expected. However, the said polymer has some difficulties in view of necessity of reactions of many steps for its synthesis that triphenylmethyl ester which is the corresponding monomer is polymerized in an organic solvent using a rhodium catalyst and then an ester group in the side chain is hydrolyzed with an acid. In view of economy, environmental problem, etc., a process for the direct polymerization of (4-carboxyphenyl)acetylene in water is preferred. However, carboxylic acid such as acetic acid has been frequently used already as a stopping agent for polymerization of acetylene monomer using a rhodium catalyst and, due to such a reason, there has been no example where acetylene monomer having an acidic site like carboxylic acid is polymerized using a rhodium catalyst. Although there is a report for dispersion polymerization of a hydrophobic monomer such as phenylacetylene in water using a rhodium catalyst, there has been no example where a water-soluble acetylene monomer is homogeneously polymerized in water.
An object of the present invention is to provide a process for the production of a polyacetylene derivative which is more preferred in view of economy, environmental problem, etc. in which the polyacetylene derivative having an ability of discrimination of asymmetry can be produced by a few steps in an easy manner and in a high yield.